面试题3：替换空格和清除空格 (二)

#include "stdafx.h"   
#include    
using namespace std;  
  
//清除字符串str中多余的空格,从前往后遍历   
void DeleteRedundantBlank(char *str)  
{  
    if (str == NULL)  
    {  
        return;  
    }  
  
    char *p1 = str;  
    char *p2 = str;  
    bool keepBlank = false;//记录空格是否保存      
  
    while (*p1 != '\0')//注意此处应该是p1,不是p2,因为'\0'仍然需要赋给p1   
    {         
        if (*p2 != ' ')  
        {  
            *(p1++) = *(p2++);  
            keepBlank = true;  
        }  
        else  
        {  
            if (keepBlank)  
            {  
               *(p1++) = *(p2++);  
               keepBlank = false;  
            }  
            else  
            {  
               p2++;  
            }             
        }         
    }  
  
    int nlen = strlen(str);  
    if (str[nlen - 1] == ' ')  
    {  
        str[nlen - 1] = '\0';  
    }  
    nlen = strlen(str);  
}  
  
int _tmain(int argc, _TCHAR* argv[])  
{  
    char str1[50] = "We are happy.";  
    DeleteRedundantBlank(str1);  
    cout << str1 << endl;  
    cout << strlen(str1) << endl;  
  
    char str2[50] = "   We    are    happy.    ";  
    DeleteRedundantBlank(str2);  
    cout << str2 << endl;  
    cout << strlen(str2) << endl;  
  
    char str3[50] = "";  
    DeleteRedundantBlank(str3);  
    cout << str3 << endl;  
  
    char str4[50] = "    ";  
    DeleteRedundantBlank(str4);  
    cout << str4 << endl;  
  
    system("pause");  
    return 0;  
}  
#include "stdafx.h"
#include 






using namespace std;

//清除字符串str中多余的空格,从前往后遍历
void DeleteRedundantBlank(char *str)
{
	if (str == NULL)
	{
		return;
	}

	char *p1 = str;
	char *p2 = str;
	bool keepBlank = false;//记录空格是否保存	

	while (*p1 != '\0')//注意此处应该是p1,不是p2,因为'\0'仍然需要赋给p1
	{		
		if (*p2 != ' ')
		{
			*(p1++) = *(p2++);
			keepBlank = true;
		}
		else
		{
			if (keepBlank)
			{
               *(p1++) = *(p2++);
               keepBlank = false;
			}
			else
			{
               p2++;
			}			
		}		
	}

	int nlen = strlen(str);
	if (str[nlen - 1] == ' ')
	{
		str[nlen - 1] = '\0';
	}
	nlen = strlen(str);
}

int _tmain(int argc, _TCHAR* argv[])
{
	char str1[50] = "We are happy.";
	DeleteRedundantBlank(str1);
	cout << str1 << endl;
	cout << strlen(str1) << endl;

	char str2[50] = "   We    are    happy.    ";
	DeleteRedundantBlank(str2);
	cout << str2 << endl;
	cout << strlen(str2) << endl;

	char str3[50] = "";
	DeleteRedundantBlank(str3);
	cout << str3 << endl;

	char str4[50] = "    ";
	DeleteRedundantBlank(str4);
	cout << str4 << endl;

	system("pause");
	return 0;
}